Continuity mistake: When Jenna sees herself in the mirror and topples backward over the shelf, there's a tall floor lamp directly behind the striped armchair with an ottoman. As Jenna gets to her feet, we also see there's nothing beside the armchair's arm. When Jenna's new appearance shocks her and she whispers, "What is happening?" the floor lamp has vanished, and now a small table with a plant appears beside the armchair. (00:14:20)
Character mistake: Jenna has Sparkle letters at her work. Wouldn't she get caught earlier?
Answer: Jenna asked the girl, "Can you tell I'm wearing underwear? Because I totally am". This is because when she was 13 just a day before, she was wearing big underwear. Now she's wearing a thong, which wouldn't be visible when wearing a dress.